1. Field of the Invention
This invention relates to a home bus system having a structure in which a plurality of room controllers are connected to a visual controller via a home bus.
2. Description of the Related Arts
A home bus system is to provide centralized control of a plurality of electric appliances. The structure of this system is such that a plurality of room controllers are connected to a visual controller via a home bus.
Each room controller serves as a terminal performing functions of monitoring and controlling the operating state of electric appliances such as electric lamps, air conditioners and the like positioned in respective rooms in a house, and acquiring data from security sensors installed in respective rooms for sensing a fire, a gas leak, trespassers and other emergencies. To establish such connection among electric appliances as mentioned above, the room controller is usually provided with a plurality of terminals.
The visual controller serves as a terminal performing the functions of acquiring data representing the operating states of the electric appliances, in order to display information on the operating states. The visual controller also displays information in response to an output from the security sensors. Users of this system issue instructions for the appliances by operating switches in accordance with the information on a screen.
To enable the visual controller to acquire data about the operating state or the security, the visual controller must be connected to the room controllers. Such an electrical connection is generally achieved by a so-called home bus or home bus line in the existing home bus system.
One of the existing home bus systems is exemplified in National Technical Report Vol. 32 No. 6, Dec. 1986. In this system, the operating states of electric appliances are indicated by color; namely, an ON state and a CLOSED state are denoted in white with a green background, and an OFF state and an OPENED state are denoted in black with an ivory background.
With such a display, however, users of the system are required to understand the operating state of the electric appliances only from the color of the visual controller screen. If users are fully accustomed to the system, this type of display allows users to utilize the system smoothly. However, if users are less accustomed to, or inexperienced with, the system, they may have difficulty in understanding the meaning of the color combinations.
Further, in this system, once the screen of the visual controller has changed to the security display in response to the output of the security sensor, the control of the electric appliance cannot be resumed without terminating the security sensor. Namely, once the security screen has appeared on the screen, it is impossible to change the screen to a screen showing a controlled state, or a control screen. While the security screen appears on the screen, the controlled state of the electric appliances is not indicated on the screen of the visual controller. This actually results in the users being unable to provide instructions to the electric appliances from the switch.
Since the transition of the screen to the security screen is only caused when am emergency has arisen, users must take some action against such a situation. In the existing system, however, the security screen merely indicates the occurrence of the emergency but does not indicate the specific room where the emergency arose, dragging the response time from the discovery of the emergency to taking action.
Electric appliances to be controlled would often be activated at a given hour by means of a timer. In the existing system set forth in the above, ON-OFF or OPENING-CLOSING control of the electric appliances adjusted to a user's life cycle on weekdays is usually achieved by the use of the timer. During a timer setting, the screen of the visual controller has indications of the ON/OFF state of the timer, a starting time of the operation of the electric appliances using the timer, and a finishing time of the operation. Usually, the life cycle of the user on weekends will be different from that on weekdays. Therefore, users were obliged to reset the timer before weekends, and vice versa on weekdays.
In the existing system, a large cathode-ray-tube which can display the operating state of all electric appliances is used as the display for the visual controller. This resulted in a bulky home bus system including the visual controller, occupying too much space.
In order to overcome the drawbacks set forth in the above and achieve an improvement in visuality and diversification of the display, a color LCD (liquid crystal display) may be used as a display means to display the state of the electric appliances.
Noticeable in recent years, there has been a tendency for the number of electric appliances used in one room to be increased. Since there are limitations in the number of electric appliances connectable with one room controller, a plurality of room controllers may need to be placed in one room, and each room controller requires its own name. Accordingly, the electric appliances connected to different room controllers positioned in the same room cannot be controlled without the designation of a different room name, the electric appliances connected to a different room controller cannot be controlled.